|
- from importlib import import_module
-
- from django.utils.version import get_docs_version
-
-
- def deconstructible(*args, **kwargs):
- """
- Class decorator that allow the decorated class to be serialized
- by the migrations subsystem.
-
- Accepts an optional kwarg `path` to specify the import path.
- """
- path = kwargs.pop('path', None)
-
- def decorator(klass):
- def __new__(cls, *args, **kwargs):
- # We capture the arguments to make returning them trivial
- obj = super(klass, cls).__new__(cls)
- obj._constructor_args = (args, kwargs)
- return obj
-
- def deconstruct(obj):
- """
- Returns a 3-tuple of class import path, positional arguments,
- and keyword arguments.
- """
- # Python 2/fallback version
- if path:
- module_name, _, name = path.rpartition('.')
- else:
- module_name = obj.__module__
- name = obj.__class__.__name__
- # Make sure it's actually there and not an inner class
- module = import_module(module_name)
- if not hasattr(module, name):
- raise ValueError(
- "Could not find object %s in %s.\n"
- "Please note that you cannot serialize things like inner "
- "classes. Please move the object into the main module "
- "body to use migrations.\n"
- "For more information, see "
- "https://docs.djangoproject.com/en/%s/topics/migrations/#serializing-values"
- % (name, module_name, get_docs_version()))
- return (
- path or '%s.%s' % (obj.__class__.__module__, name),
- obj._constructor_args[0],
- obj._constructor_args[1],
- )
-
- klass.__new__ = staticmethod(__new__)
- klass.deconstruct = deconstruct
-
- return klass
-
- if not args:
- return decorator
- return decorator(*args, **kwargs)
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